﻿using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;

namespace MONTRASEC_test
{
  public class GridViewExportUtil
  {
    /// <summary>
    /// 
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="gv"></param>
    public static void Export(string fileName, GridView gv)
    {
      HttpContext.Current.Response.Clear();
      HttpContext.Current.Response.AddHeader(
          "content-disposition", string.Format("attachment; filename={0}", fileName));
      HttpContext.Current.Response.ContentType = "application/ms-excel";

      using (StringWriter sw = new StringWriter())
      {
        using (HtmlTextWriter htw = new HtmlTextWriter(sw))
        {
          //  Create a form to contain the grid
          Table table = new Table();

          //  add the header row to the table
          if (gv.HeaderRow != null)
          {
            GridViewExportUtil.PrepareControlForExport(gv.HeaderRow);
            table.Rows.Add(gv.HeaderRow);
          }

          //  add each of the data rows to the table
          foreach (GridViewRow row in gv.Rows)
          {
            GridViewExportUtil.PrepareControlForExport(row);
            table.Rows.Add(row);
          }

          //  add the footer row to the table
          if (gv.FooterRow != null)
          {
            GridViewExportUtil.PrepareControlForExport(gv.FooterRow);
            table.Rows.Add(gv.FooterRow);
          }

          //  render the table into the htmlwriter
          table.RenderControl(htw);

          //  render the htmlwriter into the response
          HttpContext.Current.Response.Write(sw.ToString());
          HttpContext.Current.Response.End();
        }
      }
    }

    /// <summary>
    /// Replace any of the contained controls with literals
    /// </summary>
    /// <param name="control"></param>
    private static void PrepareControlForExport(Control control)
    {
      for (int i = 0; i < control.Controls.Count; i++)
      {
        Control current = control.Controls[i];
        if (current is LinkButton)
        {
          control.Controls.Remove(current);
          control.Controls.AddAt(i, new LiteralControl((current as LinkButton).Text));
        }
        else if (current is ImageButton)
        {
          control.Controls.Remove(current);
          control.Controls.AddAt(i, new LiteralControl((current as ImageButton).AlternateText));
        }
        else if (current is HyperLink)
        {
          control.Controls.Remove(current);
          control.Controls.AddAt(i, new LiteralControl((current as HyperLink).Text));
        }
        else if (current is DropDownList)
        {
          control.Controls.Remove(current);
          control.Controls.AddAt(i, new LiteralControl((current as DropDownList).SelectedItem.Text));
        }
        else if (current is CheckBox)
        {
          control.Controls.Remove(current);
          control.Controls.AddAt(i, new LiteralControl((current as CheckBox).Checked ? "True" : "False"));
        }

        if (current.HasControls())
        {
          GridViewExportUtil.PrepareControlForExport(current);
        }
      }
    }
  }
}
